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The Common clownfish is a small sized fish which grows up to 11cm. Its body has a stock appearance, oval shape, compressed laterally and with a round profile. The coloration of its body is orange to reddish-brown, but it can also be black in some particular areas like in the Northern Territory in Australia[2]. It has three vertical white stripes outlined with a fine black line. The fisrt passing just behind the eye, the second in the middle of the body is widening forward to the head centrally and the third one circles the caudal peduncle[3]. All the fins are also outlined with a fine black line. Amphiprion ocellarisis often confused with Amphiprion percula who possesses exactly the same colours and patterns at first sight but which distinguishes itself by the thickness of the black outlines[4].

Amphiprion ocellaris has a diurnal activity. It is protrandous hermaphrodite, which means the male can evolved to female during his life, and lives in harem in which an established dominance hierarchy manages the group and keeps individuals at a specific social rank. It has also an aggressive territorial behaviour and it's completly dependant from its sea anemone which represents its "life insurance" as a safe shelter for the group and for the nest[8]. The associative relationship that binds the clownfish and the sea anemone is called mutualism.In one hand, the fish can lives within the sea anemone's tentacles and uses it as a shelter because it has developped a fin layer of mucus which covers its body as a protection against the stinging anemone's tentacles. On the other hand, the presence of the clownfish can be interpreted as a lure to attract potential anemone's preys close to the tentacles. And the clownfish can also defend the anemone against some reef fishes which could eat the tentacles[9].

The species Amphiprion ocellaris belongs to the class Osteichthyes which contains bony fish and ray-finned fish. A. ocellaris is the most basal species in the genus Amphiprion which is closely related to the genera Premnas. The species' most closely related ancestor is Amphiprion percula, the Orange Clownfish. It is thought that A. ocellaris specialized after diverging from the Premnas genus, and scientific evidence confirms that all clownfish belonging to the genus Amphiprion could withstand the stings of only one type of anemone, after further diverging the 28 different species of clownfish including A. ocellaris specialized to be able to resist the poisonous stings of many different species.

The 2003 Pixar film, Finding Nemo featured a duo of Ocellaris clown fish,[10] Nemo (voiced by Alexander Gould) a juvenile clownfish, the title character/Marlin's son, and Marlin (voiced by Albert Brooks) as Nemo's overprotective father. Nemo's mother, Coral, was also a clownfish but only featured at the beginning of the film before being killed by a barracuda.